Fuel pump with rocker arm wear pad



Dec. 26; 1967 P, CASASSA 3,359,918

FUEL PUMP WITH ROCKER ARM WEAR PAD Filed June 9, 1965 IN VENTOR.

fuse 0k r? Caszmsa v Zrmzzvzy United States Patent 3,359,918 FUEL PUMP WITH ROCKER ARM WEAR PAD Joseph P. Casassa, Clio, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed June 9, 1965, Ser. No. 462,620 6 Claims. (Cl. 103-215) This invention relates to pumps and more particularly to fuel pumps of the automobile type which are operated by rocker arms each of which, in turn, is adapted to be actuated by some part of an engine such as a cam-shaft.

It is conventional to mount fuel pumps on automotive engines so that in each pump an operating rocker .arm extends into the engine for resilient or spring pressed engagement with an actuator such as a cam forming a moving part of the engine. A difficulty often arises in that a slight misalignment of the rocker arm with respect to the actuator o-r cam, because of the pump mounting or for some other reason, causes the contact area between the arm and the cam to be very limited .and sometimes so limited as to approach a mere point contact. This increases wear of either the cam or the arm or both. Rather costly shoes to absorb the wear have been interposed between such cams and rocker arms and a need has risen for a simplified, inexpensive and effective arrangement whereby misalignment of the arm and cam or actuator will not reduce the intended extent of contactual area.

To this end, the object of this invention is to produce a fuel pump with a simple rocker .arm arrangement of low cost and real effectiveness in assuring the realization of a desired contact area for absorbing wear.

A feature of the present invention is a fuel pump rocker arm having .a curved transverse surface with a flat surface shoe held in non-slidable, tiltalble and contactual relation to that surface.

This and other important features of the invention will now be described in detail in the specification and then pointed out more particularly in the appended claims.

In the drawings:

FIGURE 1 is an elevation view, partly in section, showing an automobile pump with its rocker arm arrangement in contact with an engine cam;

FIGURE 2 is an enlarged section view looking in the direction of the arrows 22 in FIGURE 1 with dot and dash lines depicting relative angles of tilt which are possible; and

FIGURE 3 is an exploded view, in perspective, of portions of the rocker arm arrangement and the cam of FIG- URES 1 and 2.

Internal details of the fuel pump illustrated are largely omitted in this description as such a pump is disclosed in the United States Patent 2,929,333 granted Mar. 22, 1960, in the name of G. W. Harry, and those details form no part of the present invention.

FIGURE 1 depicts the supporting body at of a fuel pump, this body having a recess 12 surrounded by a flange portion 14 and this flange portion is such as to provide for the attachment of the body 10 to an automobile engine by bolts not shown and as is conventional. An automobile camshaft is shown at 16 and which is provided with a cam 18. The pump is provided with a diaphragm plunger 20 which is adapted to be reciprocated with motion in one direction being effected by a spring 22 and a rocker arm generally indicated at 24. The rocker arm is pivotally mounted on a shaft 26 retained within recess 12 and the arrangement with respect to the spring 22 and the cam 18 is such that the spring 22 resiliently tends to rotate the arm 24 in one or a clockwise direction as shown in the drawing whereas the cam 18 is adapted positively to rotate the rocker arm 24 in the opposite or a counterclockwise direction. When the automobile engine is openated, the rocker arm 24 will oscillate about the shaft 26 and suction is created by the cam action and pumping is effected by the spring action.

The rocker arm 24 includes an elongated arm portion 30 of U shaped cross section as best illustrated in FIG- URES 2 and 3. The underside surface 32 of the arm portion 30 is tnansversely arcuate but is preferably linearly straight as measured along the length of the arm portion. Integral with the arm portion 30 are two tabs 34 and 36. These two tabs are T-shaped to serve as retaining means for a shoe indicated at 38. This shoe bears notches 40 and 42 at its opposite ends whereby the shoe may be interlocked with the arm portion 30 by means of the tabs 34 and 36. Preferably, the shoe 38 is made of .a piece of sheet metal of uniform thickness but this is not necessarily the case. The plate must, however, have one wear surface 48 which is flat :for proper engagement with the cylindrical surface 50 of the cam 18. FIGURE 3 is so drawn as to indicate one suitable mode of attachment of the shoe 38 to the arm portion 30. The tab 34 is first bent at right angles with respect to the surface 32 as shown in FIGURE 3. The shoe 38 is then placed with the tab 34 interlocking in the notch 40 and then the tab 38 is bent at right angles to complete the assembly of the arm portion 30 and the shoe 38. In this assembly, there is substantially no lengthwise or linear movement of the shoe 38 with respect to the rocker arm. There is sufiicient clearance allowed, however between the tabs and the shoe to permit a tiltable movement of the shoe 38 on the arcuate surface 32.

With this arrangement, a wide choice of materials may be had for the camshaft, the arm portion 30 and the shoe 48 in effecting long life potential due to the excellent alignment of the shoe 38 with respect to the cam surface 50 despite the fact that the pump or any of its driving parts may be mounted slightly out of alignment with the camshaft 16.

I claim:

1. A fuel pump having a housing, a rocker arm pivotally retained on said housing and having an oscillatab'le elongated portion extending from said housing, spring means urging said rock to rotate in one direction, a surface of said portion extending along the length of the latter and facing said one direction, said surface being straight along said length and convex across said length, a fiat shoe extending along and in tiltable relation with said surface, and means retaining said flat shoe against linear movement with relation to said surface.

2. A fuel pump having a housing, a rocker arm portion having a surface thereon linearly extending from said housing, means resiliently urging said portion to move in one direction, said surface facing said direction and being convex transverse to the width of said portion, an elongated flat shoe adjacent to along, and in tiltable relation with said surface, and means retaining said shoe against linear movement with relation to said surface but with sufiicient clearance to permit said tiltable relation.

3. A fuel pump as set forth in claim 2, a substantial length of said flat shoe being of uniform thickness as measured in a direction away from said portion.

4. A fuel pump as set forth in claim 2, said retaining means being tabs engaging said flat shoe and formed integral with said rocker arm.

5. A fuel pump as set forth in claim 2, said retaining means including tabs arranged at opposite ends of said flat shoe and forming an interlock between said flat shoe and said rocker arm with suflicient clearance to permit said tiltable relation.

6. A fuel pump having a housing, a rocker arm pivotally retained on said housing with an oscillatabl-e elongated portion extending from the latter, spring means urging said rocker arm to rotate in one direction, said portion having a surface facing said one direction and 3 4 which is convex transverse to the length of said portion, References Cited an elongatled shoe in tiltable relation with and extending UNITED STATES PATENTS along the ength of said portion, alocalized area of one 7 surface of said shoe being in contact with said convex 2,207,332 7/1940 Paxton 74 569 surface and about which said tiltable relation may be 5 2,829,541 4/1958 P 74569 effected, a second and opposite surface of said shoe being 3186350 6/1965 Fltzgerald 103 150 flat and facing in said one direction, and means retaining FOREIGN PATENTS said shoe against any substantial movement along the 664,238 10/1929 France length of said elongated portion but with Sllfl'lClCJlt clearance to permit the tiltable relation. 10 ROBERT M, WALKER, Primary Examiner. 

1. A FUEL PUMP HAVING A HOUSING, A ROCKER ARM PIVOTALLY RETAINED ON SAID HOUSING AND HAVING AN OSCILLATABLE ELONGATED PORTION EXTENDING FROM SAID HOUSING, SPRING MEANS URGING SAID ROCK ARM TO ROTATE IN ONE DIRECTION, A SURFACE OF SAID PORTION EXTENDING ALONG THE LENGTH OF THE LATTER AND FACING SAID ONE DIRECTION, SAID SURFACE BEING STRAIGHT ALONG SAID LENGTH AND CONVEX ACROSS SAID LENGTH, A FLAT SHOE EXTENDING ALONG AND IN TILTABLE RELATION WITH SAID SURFACE, AND MEANS RETAINING SAID FLAT SHOE AGAINST LINEAR MOVEMENT WITH RELATION TO SAID SURFACE. 